[Bug c++/77509] New: ICE on invalid C++ code: in finish_class_member_access_expr, at cp/typeck.c:2783

["su at cs dot ucdavis.edu" <gcc-bugzilla at gcc dot gnu dot org>]

https://gcc.gnu.org/bugzilla/show_bug.cgi?id=77509

            Bug ID: 77509
           Summary: ICE on invalid C++ code: in
                    finish_class_member_access_expr, at cp/typeck.c:2783
           Product: gcc
           Version: 7.0
            Status: UNCONFIRMED
          Severity: normal
          Priority: P3
         Component: c++
          Assignee: unassigned at gcc dot gnu.org
          Reporter: su at cs dot ucdavis.edu
  Target Milestone: ---

It affects all versions 4.8.x and later, and is a regression from 4.7.x. 


$ g++-trunk -v     
Using built-in specs.
COLLECT_GCC=g++-trunk
COLLECT_LTO_WRAPPER=/usr/local/gcc-trunk/libexec/gcc/x86_64-pc-linux-gnu/7.0.0/lto-wrapper
Target: x86_64-pc-linux-gnu
Configured with: ../gcc-source-trunk/configure --enable-languages=c,c++,lto
--prefix=/usr/local/gcc-trunk --disable-bootstrap
Thread model: posix
gcc version 7.0.0 20160906 (experimental) [trunk revision 240004] (GCC) 
$ 
$ g++-trunk -c small.cpp
small.cpp:3:8: warning: direct base ‘A’ inaccessible in ‘C’ due to ambiguity
 struct C : A, B {};
        ^
small.cpp: In function ‘void foo()’:
small.cpp:8:8: internal compiler error: in finish_class_member_access_expr, at
cp/typeck.c:2783
   c.C::m < int > ();
        ^~~~~~~~~
0x7e8254 finish_class_member_access_expr(cp_expr, tree_node*, bool, int)
        ../../gcc-source-trunk/gcc/cp/typeck.c:2783
0x79dd04 cp_parser_postfix_dot_deref_expression
        ../../gcc-source-trunk/gcc/cp/parser.c:7364
0x79b54c cp_parser_postfix_expression
        ../../gcc-source-trunk/gcc/cp/parser.c:6967
0x799e6c cp_parser_unary_expression
        ../../gcc-source-trunk/gcc/cp/parser.c:8019
0x7a3d17 cp_parser_cast_expression
        ../../gcc-source-trunk/gcc/cp/parser.c:8696
0x7a4315 cp_parser_binary_expression
        ../../gcc-source-trunk/gcc/cp/parser.c:8798
0x7a4c00 cp_parser_assignment_expression
        ../../gcc-source-trunk/gcc/cp/parser.c:9086
0x7a74f9 cp_parser_expression
        ../../gcc-source-trunk/gcc/cp/parser.c:9253
0x7a7b1f cp_parser_expression_statement
        ../../gcc-source-trunk/gcc/cp/parser.c:10736
0x7b645c cp_parser_statement
        ../../gcc-source-trunk/gcc/cp/parser.c:10587
0x7b73dc cp_parser_statement_seq_opt
        ../../gcc-source-trunk/gcc/cp/parser.c:10859
0x7b74cf cp_parser_compound_statement
        ../../gcc-source-trunk/gcc/cp/parser.c:10813
0x7b767f cp_parser_function_body
        ../../gcc-source-trunk/gcc/cp/parser.c:20832
0x7b767f cp_parser_ctor_initializer_opt_and_function_body
        ../../gcc-source-trunk/gcc/cp/parser.c:20868
0x7b8121 cp_parser_function_definition_after_declarator
        ../../gcc-source-trunk/gcc/cp/parser.c:25565
0x7b8e35 cp_parser_function_definition_from_specifiers_and_declarator
        ../../gcc-source-trunk/gcc/cp/parser.c:25477
0x7b8e35 cp_parser_init_declarator
        ../../gcc-source-trunk/gcc/cp/parser.c:18603
0x7b9189 cp_parser_simple_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:12495
0x7b94c1 cp_parser_block_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:12363
0x7c22a0 cp_parser_declaration
        ../../gcc-source-trunk/gcc/cp/parser.c:12260
Please submit a full bug report,
with preprocessed source if appropriate.
Please include the complete backtrace with any bug report.
See <http://gcc.gnu.org/bugs.html> for instructions.
$ 


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struct A {  template < class > void m ();  };
struct B : A {};
struct C : A, B {};

void foo ()
{
  C c; 
  c.C::m < int > ();
}